Processing and Properties of Ion Exchanged Glasses Jill Glass and Raj Tandon Sandia National Labs, Albuquerque, NM Prof. Arun Varshneya and Ian Spinelli Saxon Glass Technology, Inc. Glass and Optical Materials Division Fall Meeting Cape Canaveral, FL Nov. 6-12, 2004 Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy’s National Security Administration under Contract DE-ACO4-94AL85000.
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Processing and Properties of Ion Exchanged GlassesProcessing and Properties of Ion Exchanged Glasses Jill Glass and Raj Tandon Sandia National Labs, ... • Corning 0317 has greater
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Processing and Properties of Ion Exchanged Glasses
Jill Glass and Raj TandonSandia National Labs, Albuquerque, NM
Prof. Arun Varshneya and Ian SpinelliSaxon Glass Technology, Inc.
Glass and Optical Materials Division Fall MeetingCape Canaveral, FL
Nov. 6-12, 2004
Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy’s National Security Administration under Contract DE-ACO4-94AL85000.
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Recent Severe Hailstorm in New Mexico
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Truck Bomb Attacks on Federal Buildings Have Focused Attention on Glass Behavior
Embassy in NairobiAugust 7, 1998 Truck Bomb
Embassy in Dar Es SalaamAugust 7, 1998 Truck Bomb
1995- Murrah Building, Oklahoma City, OK
1996- Khobar Towers, Saudi Arabia
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Glass Fragment Character and Size, and Glass Strength Depend on Processing
Plate Glass- 5 kg Indent Plate Glass - As-Rec’d Ion Exchanged
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Video
To view the video showing the breaking glass sheet for
standard glass compared to ion exchanged glass
use the link on the IMI-NFG website orhttp://rm1.cc.lehigh.edu:8080/dept/IMI/EdVideo/RealTime&SloMoGlassBreakage.mpg
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Exchange of a Na-containingglass in a bath of molten KNO3 salt
Ion Exchange Process Replaces Small Ions in Glass Surface with Large Ions
K
Na
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Ion Exchange Stress Profile Increases Glass Strength and Fragmentation
12 hr exchangeStrength = 759 MPa
48 hr exchangeStrength = 706 MPa
Tension
Compression
Glass Thickness
Magnitude of surface compressive stress determinesstrength
Magnitude of central tension determines fragmentation
Disk diameter=1 inchStress profile = - - - - - -
The more a crack branches as it propagatesthe greater the degree of fragmentation.
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Fragment Size Largely Determined by Central Tension, σt and Crack Branching Behavior
( )( )δ
νσ −
+=ttKx
t
c
5.012
21Fragment size,
KIC=toughness, t=thickness, δ=ion exchange depth
tδx2
δ
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Schott Robax and Corning 0317 Glass Exchanged at 450 & 500C for Different Times
• Ion exchange provides remarkable damage tolerance and strengthening of glass
• Indentation induced fragment size determined by branching distance (central tension, t, δ) and number of branches
• Corning 0317 has greater ion exchange depth and central tension than Schott Robax for a given exchange time and T
• For similar values of central tension Corning has greater degreeof fragmentation than Robax because of lower toughness (0.82 vs. 1.09 MPa.m0.5, ratio=0.75)
• Critical σt for fragmentation is ~ 34 MPa for 2.2 mm Corning and just below 47 MPa for Robax (ratio=0.72)
• Glasses with higher KIC require higher central tensions to achieve fragmentation and have larger fragments for a given σt
• High values of surface compression and strengths can be achieved for Schott Robax - K+ for Li+ exchange
• High strengths, even for long exchanges, suggest that fracture controlled by compressive maximum
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Acknowledgments
• Clay Newton and Ed Beauchamp, Sandia National Labs
• Students: Jason Kooi, Erica Hoover, Jen Rygel, Roman Wolf-Cecil, Karl Nieman, Luke Degruyter
• D. Gerling, Sierracin/Sylmar Corp., Sylmar, CA
Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy’s National Security Administration under Contract DE-ACO4-94AL85000.